A thesis has to have something new. It’s not just a collection of words. Ideas, facts, interpretation – whatever you could summarise it as, there’s something new in there. Something that wasn’t there before your PhD. Maybe something that could never have been done until now. Maybe something that could never have been done until YOU came along.
Don’t undersell the contribution you’ve made. It only exists in your thesis because of your efforts. As you prepare for the viva, take time to unpick the novelty of your work.